The invention relates to a circuit element having a first layer composed of an electrically insulating substrate material, a method for a producing a circuit element, bispyridinium compounds and their use in circuit elements.
1. Field of the Invention
Conventional microelectronics, which are based on silicon components such as CMOS chips (CMOS: complementary metal-oxide-semiconductor), will also be reaching their limits as miniaturization progresses further. Molecular electronics are being discussed as one of the possible ways to reduce the size of components further.
In addition to the general problem of developing circuit elements with the aid of molecular electronics, a further aspect under consideration in this context is the development of alternatives to the previous semiconductor memory elements such as DRAMs (Dynamic Random Access Memories), SRAMs (Static Random Access Memories) or Flash memories.
2. Description of the Related Prior Art
It is known from [1] that monomolecular layers based on rotaxanes can be used to produce configurable circuit elements which can be used to form logic gates. This is based on the fact that the monomolecular layers of the rotaxanes can be changed, that is to say “switched”, from a conductive state to a less conductive state by application of a voltage. However, this switching process as is known from [1] is irreversible and is thus suitable for a write once/multiple read application.
It is known from [2] that a reversible switching process can be achieved with the aid of a further specific molecule class, which are referred to as catenanes. However, very low signals are observed during this switching process. Furthermore, [22] describes the use of specific catenanes in circuit elements which have a monomolecular layer composed of these catenanes.
However, the two circuit elements which are known from [1] and [2] also have further disadvantages for widescale practical use. On the one hand, rotaxanes and catenanes are available only by complex synthesis processes. On the other hand, Langmuir-Blodgett methods are used to produce the monomolecular layers for both circuit elements. Furthermore, the suitability of these Langmuir-Blodgett methods for the coating of surfaces of components such as silicon wafers, which are normally used for producing electrical components, is still uncertain.
In addition to the approaches just discussed for development of circuit elements based on organic molecular layers, it is known from [3] for an electrical switch to be produced by the specific combination of a molecule with a bispyridinium unit and a nanoparticle (metal cluster) composed of gold. Since nanotechnology is still in its infancy, it is questionable whether this system can be used for a practical application in the foreseeable future.
Furthermore, [23] describes a molecular electronic arrangement in which, although redox-active bispyridinium molecules can be used, the arrangement has a spacer between two conductor tracks, however.
A memory cell is also known from [24] which comprises at least four electrically conductive layers arranged one above the other.
Furthermore, the Laid-Open Specification [25] discloses electrochrome compounds and electrochrome apparatuses based on these compounds. In a similar way to [25], [26] discloses soluble polymers and their use in electrochrome apparatuses. Finally, [27] discloses photosensitizers based on ruthenium (II) complexes.